Purge arrangement for heating coils



Jan. 13, 1948. NOBLE P URGE ARRANGEMENT FOR HEATING COILS Filed April 8, 1944 2 Sheets-Sheet l INVENTOR.

Jan. 13 1948. NOBLE 2,434,580

PURGE ARRANGEMENT FOR HEATING COILS Filed April 8, 1944 2 Sheets-Sheet 2 IN V EN TOR.

19770E/YEY Patented Jan. 13, 1948 New Jersey Thi invention relat s" to heat exchang ,The general object r tl e inventionig'f'teproi e' el pine n s to m in le 2 a qdnglitioner lmusir g fqrmir ig we casing" (if 5 fanjblgst syl n'e s Insuch systems it' isi usual t6 halje outdpq alii, eithef alp'ne er in combine;- uoh wimr tum' rif fohe'prdportioh's"iqheredf be; mg regulated by hand contr'olled or automatically cofitrel'led clampefsg the air efitering the hdu'sing tgi p'ej hated by qne qr more coils positicined w ithiyilthe housingu Afan or blower delivei's the' Iieafted air through a, series of ducts tqiioi' mureenclbsures tqlcie heate'd. In conheetioli with the 'epxjare'tus hpwp in Fig; 1,- the air' intal'arigi dlscliarfg' arran me ts are; not shown siuce" they anje well lmbwri iii the art and f dr'n'n' n6 part of this" invention.

mad 'of h ee meta-1 qr-me like so that air pune'a' ljifal nf'l will necessarily pass through encased heatilfi'gfeoilfl which 1's confinedw thmmusmgm g Heating coil 8 comprises a, casing 9 within which are suitably supported Supply header" Ill aha retur'nheader H. Steam from a'lsciui -ce of supply, sucha s a boiler, is admitted through feed litie' I 2 tq sup'bly header l0. Heating surfax'ie, pyefei'aikily' in phe t rm of a plurality of finne tubes" l3, gonnec't the' supply header' t'othe r'e turri heaid ep; Onesuch tube is shownin Fig: 1, but it will'be-undet'stobd that'in practid afn'um-j ber' o' f' such, tubes pbnn e'ct' the hea'der' tqgether; the tiibes' beit1g po'sitioneq closely together So: that thei air pulled by' fan 1" will effetivelyfi heated by cqntactj with tubes l 3; wii;h=t he by; pals-sing feicfior held po a spebified minimum. Re; turn lihe' Hf is cor mect edto rtuifn header H by cormect ir'i'g'" line I51 Clean-out portienlliis pie; vided at the lpwer end ofline' I5 sdthat new substatifqially free of sqlid matte!" will take plice frbm'li ne Ifiifito: line H; l

{is is cununqn'm such systems/air arid-1 other nOn cjQnd'eMJbIe gases enter the tubes cqmprlfs'; meme heating surface 'with the result that up: 6 1 $3 1 ndn-b n e l gases arele iflm d cdrr'oswn takes place within the tubes and-eifi-L clency in heat exchange is reduced: 1 f

To assure efiective purging, applieant 'prpvides purge" line l lileading" from-l return' h'eader- H preferablyhaving; bqdy pprpion in the" for'mfo'i a seibentine sec gondaryu elief c'oil' l8 positioned I th'efiow of air e tering hou ing}: Coil l8 cbficondenser or air relief coil separate from the heating coil. The connection of this secondary coil to return header ll assures complete purging of all air and non-condensable gases which are forced into the secondary coil. Since the cold air stream pulled by the fan first strikes the secondary coil, the condensing action therein is efl'ectlve and the pressure of steam from header H is sufiicient to keep this coil clean. The result is an active passage of condensate and non-condensables from the secondary to the return line, thereby assuring complete purging of the tubes of the heating coil 8.

In Fig. 2 a plurality of coils 8A, 8B, 8C, and 8D are positioned within conditioner housing 3 and the air pulled by fan 1 passes through the series of heating coils in the direction shown by the arrow. In this arrangement, steam from feed line l2 first enters the supply header of coil 8D leaving from the return header thereof through discharge line 23D. Condensate Will flow from discharge line 23D to return line l4, trap 24D being interposed in the usual manner. However, the steam leaving the return header at the bottom of coil 8D will fiow through line 25D to the supply header of coil 8C. This steam and condensate will leave the return header of coil 8C flowing through discharge line 230. The condensate will fiow to discharge line I4 through trap 24C but the steam will go through line 250 to coil 8B where the action will be repeated with the steam flowing from the supply header to the return header of coil 83 and leaving through discharge line 23B. The condensate from line 233 flows; to return line l4 through trap 24B and the steam goes through line 253 to the last coil 8A. The steam passes from the supply header to the return header of coil 8A; and the condensate and steam flow from discharge line 23A through trap 24A to return line H. Air vent 26 connects to discharge line 23A. 1 The coldest air first enters coil 8Awhere the steam'pressure is least and where the mean effective difference between the heating surface and the air is greatest. This is conducive to effective condensation in coil 8A with the result that purging will be assured in this coil where it is most required. The non-condensables in the first three coils will either leave through discharge lines 23D, 23C, and23B or enter coil 8A. The effective condensing action in coil 8A assures relief of the non-condensablesfrom this coil. The steam pressure is adequate to achieve such purging in view of the efiective condensing action. Air vent 26 connected to discharge line 23A aids relief-of air from the system.

The piping arrangements of Figs- 1 and 2 assure complete purging by removal of non-condensable gases from the greater portion of heat exchange surface and by providing eifective condensing action either in auxiliary coil or in a small portion of the surface used in a multiple coil arrangement from which the gases are effectively delivered.

I claim: 1. A method of purging a steam heating coil which consists in admitting steam to a supply header, passing steam from the supply header through a plurality of tubes to a return header, withdrawing condensate from the return header directly to a return line, passing steam and noncondensable gases from the return header through a secondary coil disposed adjacent the steam coil to condense the steam, returning the condensate to a return line, and'passing air to be heated first through the secondary coil and then through the steam coil whereby condensation in the secondary coil serves effectively to withdraw noncondensable gases from the steam coil.

2. A method of purging a series of heating coils which consists in admitting steam from a source of supply to the supply header of a first steam coil,,routing the steam downwardly through tubes of the first steam coil to a second header, routing condensate from the second header to a return line while routing the steam from the second header to the supply header of a second steam coil, said steps being repeated for each coil employed in the series except the last coil, purging non-condensible gases from the last coil, removing condensate from the last coil to the return line, and passing air in contact with the coils in a direction from the last to the first coil whereby a the coldest air contacts the coil wherein the steam pressure is least to bring about effective condensation in the last coil to assure purging of noncondensible gases from the heating coil and to induce flow of non-condensible gases through the other coils.

3. A piping arrangement for assuring purging of non-condensible gases from a steam heating coil comprising a supply header, a return header, a plurality of tubes connectin the supply header and the return header, a steam supply line leading to the supply header, a return line leading from the return header, a secondary gas relief coil disposed adjacent the finned tubes of the steam heating coil, a line connecting the return header to the entrance end of said relief coil, means connecting the discharge end of the relief coil to the return line, and means for passing air to be heated first through the relief coil and then through the heating coil to effect condensation in the relief coil to purge non-condensible gases from the heating coil.

4. A piping arrangement for assuring purging of non-condensible gases from a plurality of steam heating coils which comprises a series of coils, each coil having a supply header and a return header connected by a series of tubes, a steam supply line connected to the supply header of the first coil of the series, similar pipes connecting each return header of a preceding coil to a supply headerof a succeeding coil, the last coil of the series serving as a gas relief coil, a return line connected to the return headers, and means for passing air ,to beheated first through the relief coil and then through the remaining coils to effect condensation in the relief coil to purge non-condensible gases from the coils.

5. A piping, arrangement for purging non-condensable gases from a steam heating coil including a coil having a supply header and a return header, means for supplying steam to the supply header, a return line, a connecting line having a trap device therein and connecting said return header and return line, a purge line connected to said trap device and connecting said return header and return line, said purge line having a portion thereof positioned in the path of an air stream Passing through the coil.

6. In apparatus of the character described, the combination of a casing, a steam heating coil in said casing, said coil including a supply header connected to a source of supply of steam, a return header, and a plurality 0i tubes connecting the supply and return headers, a secondary coil in the casing disposed adjacent the tubes of the heating coil, a line connecting the return header with the entrance end of the secondary coil, 9.

5 return line, a. third line connecting the return header with the return line to permit condensate to pass to the return line, a trap in the third line, a line connecting the secondary coil with the third line at a point up stream from said trap to permit condensate from the secondary coil to pass to the return line, and a fan in said casing adapted to pass air to be heated first through the secondary coil and then through the heating coil to effect condensation in the secondary coil thereby purging non-condensible gases from the heating coil.

MILNER NOBLE.

REFERENCES CITED The following references are of record in the file of this patent:

Number UNITED STATES PATENTS 

